Related links:

Cassini Flyby Dangerous for Earth News story originally written on August 16, 1999

The Cassini space probe will use the Earth's gravity to increase its speed while zooming towards Saturn. NASA's most expensive unmanned spacecraft has already made a flyby of Venus during its two-year trip in space. After passing Earth, it has one more flyby of Jupiter in 2000 before reaching Saturn in 2004. NASA probes have completed successful flybys of Earth since 1973, but this one attracts more attention than usual because the probe carries plutonium.

Plutonium is used in Cassini to power all of its instruments. Solar energy, which is the usual source of power, cannot be used because Cassini is going to Saturn. It would need solar panels the size of tennis courts in order to absorb enough energy. The satellite will come within 725 miles of Earth, which could possibly endanger lives if something happens to the spacecraft.

Plutonium is a radioactive chemical which can cause lung cancer if inhaled. The plutonium is stored as pellets in special cartons aboard Cassini, but if an error occurs, the satellite could burn up in the atmosphere and disperse the harmful chemicals. Scientists say the chance of a problem occurring is less than 1 in a million. Still, the chance of disaster upsets many around the world.

If a pellet breaks up into powder high in Earth's atmosphere, it will be dispersed all over the globe. Such a small amount will not be harmful. However, if a cannister makes it to Earth and crashes, the chemicals would be concentrated in one area.

You might also be interested in:

A spacecraft named Cassini will study the planet Saturn for several years. Cassini blasted off from Earth in October 1997. After flying past Venus, Earth, and Jupiter, Cassini finally arrived at Saturn...more

It was another exciting and frustrating year for the space science program. It seemed that every step forward led to one backwards. Either way, NASA led the way to a great century of discovery. Unfortunately,...more

The Space Shuttle Discovery lifted off from Kennedy Space Center on October 29th at 2:19 p.m. EST. The weather was great as Discovery took 8 1/2 minutes to reach orbit. This was the United States' 123rd...more

A moon was discovered orbiting the asteroid, Eugenia. This is only the second time in history that a satellite has been seen circling an asteroid. A special mirror allowed scientists to find the moon...more

Will Russia ever put the service module for the International Space Station in space? NASA officials want an answer from the Russian government. The necessary service module is currently waiting to be...more

A coronal mass ejection (CME) happened on the Sun early last month. The material that was thrown out from this explosion passed the ACE spacecraft. The SWICS instrument on ACE has produced a new and very...more

J.S. Maini of the Canadian Forest Service called forests the "heart and lungs of the world." This is because forests filter air and water pollution, absorb carbon dioxide, release oxygen, and maintain...more